CHICAGO – Postmenopausal African American women with subclinical atherosclerosis appear to be more resistant to the anti-inflammatory effects of daily aspirin than their white counterparts.
In a 6-month, double-blind, placebo-controlled pilot study, daily aspirin at 325 mg showed essentially no impact on high-sensitivity C-reactive protein (hsCRP ) levels in the African American women. Moreover, their levels of interleukin-6 (IL-6) actually shot up while on aspirin. In contrast, levels of both proinflammatory markers declined markedly with aspirin therapy in the white women, Dr. Nora Alghothani reported at the joint meeting of the International Congress of Endocrinology and the Endocrine Society.
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Postmenopausal African American women may have a blunted response to the anti-inflammatory effects of aspirin.
"Given apparent ethnic differences in response to aspirin-mediated anti-inflammatory benefits, perhaps a higher dose of aspirin may be required in African American women already at higher risk of inflammatory disease processes in order to reduce cardiovascular disease outcomes and lessen disparities," concluded Dr. Alghothani, of the department of endocrinology at the Ohio State University in Columbus.
This remark lit a four-alarm fire among audience members. They were quick to emphasize that aspirin at doses greater than 325 mg/day is associated with a sharply increased risk of bleeding and should thus not be considered as part of an individualized cardioprevention strategy for African American women unless and until there is solid evidence that the benefits outweigh the risks.
Dr. Alghothani concurred that a large-scale dose-response study is needed. In the meantime, though, the take home message of her pilot study is that physicians should not necessarily expect the same robust cardiovascular benefits with daily aspirin in their postmenopausal African American patients as in other populations, she added.
The pilot study included 42 postmenopausal, nondiabetic women with evidence of subclinical atherosclerosis based upon carotid intimal medial thickness measurements. Half were African American; half were white. Participants in each group were randomized in double-blind fashion to 6 months of aspirin at 325 mg/day or placebo, with fasting blood samples and anthropomorphic measurements obtained at baseline and 6 months. Consistent with findings from much larger studies, the African American women were heavier, with a mean body mass index of 32.8 kg/m2, compared with 27.8 kg/m2 for the white women. The African Americans also had significantly lower triglycerides and higher apolopoprotein A-I levels; however, the two groups didn’t differ in terms of fasting insulin or glucose, high-density lipoprotein, low-density lipoprotein, or blood pressure.
Dr. Nora Alghothani
In the aspirin-treated African American women, levels of hsCRP remained static over time, going from a mean of 4.53 mg/L at baseline to 4.62 mg/L at 6 months. In placebo-treated African American women, however, hsCRP jumped from 3.34 mg/L at baseline to 8.36 mg/L at follow-up.
The mean hsCRP in white women on aspirin dropped from 2.13 to 1.6 mg/L over the course of 6 months, while with placebo it went from 2.19 to 2.69 mg/L.
Levels of IL-6 in aspirin-treated African American women climbed from 0.93 pg/mL at baseline to 2.56 pg/mL at 6 months. In contrast, mean IL-6 levels in white women on daily aspirin fell from 2.69 to 1.39 pg/mL. White women on placebo experienced a rise in IL-6 from 0.58 to 2.97 pg/mL.
Most of these differences didn’t achieve statistical significance because of the small sample size, but the consistent trends suggest an overall blunted response to the anti-inflammatory effects of aspirin among African Americans, according to Dr. Alghothani. She added that these findings might help explain the well-documented ethnic disparities in cardiovascular outcomes, whereby African American women have a significantly higher cardiovascular mortality rate than white women despite on average having higher HDL and lower triglycerides.
Her study was funded by the Ohio State University Center for Women’s Health. She reported having no financial conflicts.